Fluid-pressure brake.



W. V. TURNER.

FLUID PRESSURE BRAKE.

APPLIGATION'IILED JAN. 1. 1909.

1,108,947. Pa nted S pt. 1.1914.

WITNESSES INVENTOR THE Ohms PETERS CO PHOTO-LIYHO. WISHINGION. D. I.

i To all'wiiom it may concern:

fvi'rALTEn v; TURNER, on n-Dc-Evvoon'rnivivsvnvaiv mnssrenonTo THE WESTING- or PENNSYLVANIA.

i-iousn AIR BRAKE COMPANY, or PITTSBURGH, rnnivsynvnn a, A oonronn'rron FLUID-PRESSURE BRAKE.

Specification of Letters Patent. Patented '1, 1914 Application filed January "7, 1909; Serial so; 471,134; I

-Be it known that I, VVALTER V.

Edgewood, in the county ofAlleglieny and State of Pennsylvania, have invented new and usefulImprovements 1n Fluid-Pressure Brakes, of which the following is a speci- I fitting equalizing piston than formerly-in connection with the brake valve in order to prevent leakage arOund the piston as much as possible, as this leakage tends to equalize the'opposing pressures on'the piston and thereby keep the discharge valve from seating, so that a greater than desired reduction in train pipe pressureis produced. Ithas been found, howeverythat in some cases where tight fitting pistons are employed, when it is desired to make a second application of the brakes immediately following a first application, for example, as in making a two application stop in railway passenger service, an excess of pressure over that in the train pipe sometimes occurs on the equalizing reservoir side of the piston, due to the movement of the brake valve first to full release. position after naking' the primary -applicationofthe brakes and then to lap position, in which the higher pressure in the equalizing reservoir cannot equalize with the train pipe pressure on account of the tight equalizing piston andso, the pres sure in the train pipe equalizing throughout the length thereof as heretofore, quite a difference may exist between the pressures in the equalizing reservoir and train pipe such that when the second application of the brakes is attempted, there is liable to be no further reduction in train pipe pressure or at least not to the degree contemplated by the engineer, as the movement of the brake valve may only serve to reducethe higher pressure in the equalizing reservoir to the normal train pipe pressure.

The principal object of. my present invention is therefore to provide means for Tunisian, a citizen of the United States, residing at automatically relieving any 'excess pressure occurring onthe equalizing piston. f In the accompanyingdrawing, the s ngle 1 UN $TATES PATEN'LOFFl a figure is a side elevatiompartly in section,

of a brake va'lve embodying my] improve ment, i

The-brake valve illustrated in the drawingcomln ises a casing 1 containing the usual rotarylvalve, the operation of which" is ef fected by the brake valve handle 2.; An

equalizing piston 3 forms a movable parti tion between chamber 4:" above the piston and open to an equalizmg reservoir in the usualmanner and a chamber 5'on the opposite side of'the piston which is open to the train pipe, and a said piston is adapted to operate an equalizing discharge valve 6 for controlling the exhaust of air from the train pipe to the atmosphere.

, ts so far described the brake valve is of the usual construction, and as well; known, the chamber 4 above the piston 3 is adapted to charge up with the train pipe in the running and release positions of the brake valve. 7 When the brakes are to be applied, the handle 2 is moved to service application position in which air is discharged from the chamber. {L to the atmosphere, the handle being moved backtolapposition when the desired reduction in pressure is obtained. The higher train pipe pressure in chamber 5 then forces the pistonupward and unseat-s the discharge valve ,6 Air thereupon flows from the train'pipe to" the atmosphere and continues to flow until the train pipe presfs ure is reduced to slightly less than the pressure in the chamber l, when the preponderating pressure in chamber at forces the pis ton 3 downwardly and closes the discharge valve 6. t

According to my improvement, the equalizing piston is constructed so as to permit of a farther downward movement thereof beyond thenormalclosed position in which extreme position communication is opened around the piston through one or more equalizing grooves 7. v In order to permit thi relative movement of the piston,the discharge valve 6 is made movable with respect to the piston, preferably being mounted in a chamber Sin the equalizing piston 3 and is yieldingly maintained in its normal relative position by means of a coil spring 9, a shoulder 11 being provided on the stem 10 of the 9, closing the grooves 7. It will now be apvalve, .so as to determine or limit the outward movement of the valve.

In the normal position of the parts, as shown in the drawing, the piston 3 forms a tight joint between the chambers 4 and 5, on its opposite sides, with the discharge valve closed, and the operation is the same as with the ordinary equalizing discharge valve, but should the pressure above the piston in chamber 4 exceed the train pipe pressure below the piston, then it willbe seen that the piston 3 is moved downwardly beyond its normal position, while the discharge valve 6 remains seated, and communication is opened around the piston through the grooves 7 Air then flows from the chamber and the equalizing reservoir through said grooves to the train pipe until substantial equalization of pressures is attained, when the piston 3 is automatically returned to its normal position by the action of the spring parent that I have provided a simple means whereby any excessof pressure occurring above the equalizing piston is automatically relieved.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is

1. In a brake valve, the combination with I means for supplying fluid to the train pipe for releasing the brakes, a movable abutment subject to the opposing pressures of the train pipe and a chamber and independent of said means and valve means operated by said abutment for controlling the discharge of air from the train pipe, of a restricted port opened by an excess of fluid pressure on the chamber side of said abutment for equalizing the fluid pressures on opposite side of said abutment.

2. In a brake valve, the combination with a movable abutmentsubject to the opposing pressures of the train pipe and a chamber, 7

valve, means operated by said abutment for controlling the discharge of air from the train pipe and means separate from said abutment for supplying fluid to the'train pipe of restricted ports controlled by the movement of said abutment and adapted to be opened by an excess of fluid pressure on the chamber side of said abutment to permit the fluid pressures on opposite sides of the abutment to equalize.

In a brake valve of the usual type havsupplied to the train pipe, the combination with an equalizing discharge valve mechanism comprising a piston subject to the opposing pressures of the train pipe and a chamber, a valve operated thereby for controlling the discharge of air from the train pipe, and restricted ports adapted to be opened by the movement of said piston under an excess of pressure in said chamber for permitting the equalization of fluid pressures uponopposite sides of said piston.

4. In a brake valve of the usual type having a direct passage through which fluid is 'Witnesses:

WM. M. GADY, A. M. CLnMEN'rs,

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patent;

' Washington, D. 0."

ing a direct passage through which fluid is' supplied to the train pipe in running and 

